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J. García , E. Gallego, E. Migoya, A. Crespo (UPM)

An Intercomparison Exercise on the Capabilities of CFD Models to Predict Deflagration of a Large-Scale H 2 -Air Mixture in Open Atmosphere. J. García , E. Gallego, E. Migoya, A. Crespo (UPM) A. Kotchourko, J. Yañez (FZK) , A. Beccantini (CEA) ,

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J. García , E. Gallego, E. Migoya, A. Crespo (UPM)

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  1. An Intercomparison Exercise on the Capabilities of CFD Models to Predict Deflagration of a Large-Scale H2-Air Mixture in Open Atmosphere J. García, E. Gallego, E. Migoya, A. Crespo (UPM) A. Kotchourko, J. Yañez (FZK), A. Beccantini (CEA), O.R. Hansen (GexCon), D. Baraldi (JRC), S. Høiset (N-H), M.M. Voort (TNO), V. Molkov (UU)

  2. Standard Benchmark Exercise Problems  SBEPs Objectives: establishing a framework for validation of codes and models for simulation of problems relevant to hydrogen safety, identifying the main priority areas for the further development of the codes/models. SBEPs in HySafe

  3. The experiment was performed by the Fraunhofer Institut Chemische Technologie (Fh-ICT), Germany in 1983. 20 m diameter polyethylene hemispheric balloon (total volume 2094 m3). Homogeneous stoichoimetric hydrogen-air mixture. Experiment description

  4. Initial conditions: Pressure: 98.9 kPa Temperature: 283 K. Pressure dynamics was recorded using 11 transducers, installed on the ground level in a radial direction at different distances from the centre. The deflagration front propagation was filmed using high-speed cameras. Experiment description

  5. Experiment description

  6. Experiment results Variation of flame front contours with time.

  7. Experiment results The flame front radius vs. time

  8. Organisations and codes participating

  9. Models

  10. Models

  11. All experimental results were known before the calculations. Comments about results • The influence of the polyethylene film and wire net was supposed negligible. • Sensors at 2, 8 and 18 m have to be influenced by combustion because they do not recover ambient pressure.

  12. Dynamics of the flame front radius with time

  13. Pressure dynamics at R= 2 m Flame front reaches the sensor

  14. Pressure dynamics at R= 5 m Flame front reaches the sensor

  15. Pressure dynamics at R= 8 m Flame front reaches the sensor

  16. Pressure dynamics at R= 18 m Flame front reaches the sensor

  17. Pressure dynamics at R= 35 m

  18. Pressure dynamics at R= 80 m

  19. Video: FzK

  20. Video: GexCom Flame velocity Pressure

  21. Video UU

  22. The flame velocity is reproduced quite well in most of the calculations. The pressure dynamics obtained numerically are in good agreement with the experiments for the positive values. Negative pressures are more sensitive to far field boundary condition, this can be avoided using larger domains and finer grids. More benchmarks will be necessary to calibrate and improve the codes. Conclusions

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